from django import forms
from django.db.models import Case, When, IntegerField

from .models import Maintainer, Contact, InetNum, ASBlock, ASNumber
from .validators import HandleValidatorWithSuffix, IP46CIDRValidator
from .formfields import MultiTextInput

import ipaddress


class WhoisObjectFormMixin(object):
	def __init__(self, user, *args, **kwargs):
		super(WhoisObjectFormMixin, self).__init__(*args, **kwargs)
		self._user = user

		instance = getattr(self, 'instance', None)
		if instance and instance.pk:
			self._create = False
			#self.fields['handle'].disabled = True
		else:
			self._create = True

		self.fields['handle'].help_text = "Handle for this object in uppercase with a suffix of -%s" % instance.handleSuffix

		# only show users contacts and already present contacts
		mnts = self._user.maintainer_set.all()
		if 'admin_c' in self.fields:
			self.fields['admin_c'].queryset = Contact.getMntQueryset(mnts, self.instance, "admin_c")

	def clean_handle(self):
		HandleValidatorWithSuffix(self.instance.handleSuffix)(self.cleaned_data['handle'])
		return self.cleaned_data['handle']

	def clean(self):
		cleaned_data = super(WhoisObjectFormMixin, self).clean()
		if cleaned_data.get("handle") == "AUTO" and not self.errors:
			name = cleaned_data.get("name")
			if name is None:
				name = self._user.username

			cleaned_data['handle'] = self._meta.model.genGenericHandle(name)

		return cleaned_data


class MntFormMixin(object):
	protectedFields = []

	def __init__(self, lower=False, *args, **kwargs):
		super(MntFormMixin, self).__init__(*args, **kwargs)

		self._editLower = lower

		if self._editLower:
			for key in self.protectedFields:
				self.fields[key].disabled = True

		instance = getattr(self, "instance", None)
		if not hasattr(self, "_create"):
			self._create = not (instance and instance.pk)

		mntWhens = [When(auth=self._user, then=2)]
		if not self._create:
			mntWhens.append(When(handle__in=instance.mnt_by.all().values_list("handle"), then=1))
		mntQs = Maintainer.objects.annotate(card=Case(*mntWhens, default=0, output_field=IntegerField())).order_by("-card")
		# NOTE: We cannot use distinct on a field as some db backends don't support it
		#self.fields["mnt_by"].queryset = mntQs.distinct("handle")
		self.fields["mnt_by"].queryset = mntQs

		if "mnt_lower" in self.fields:
			self.fields["mnt_lower"].queryset = mntQs


	def clean(self):
		cleaned_data = super(MntFormMixin, self).clean()

		if not self.errors and self._create:
			mnts = self._user.maintainer_set.all()

			for mnt in cleaned_data['mnt_by']:
				if mnt in mnts:
					break
			else:
				raise forms.ValidationError("On object creation at least one maintainer needs to be under your control")

class MntForm(WhoisObjectFormMixin, forms.ModelForm):
	class Meta:
		model = Maintainer
		fields = ['handle', 'description', 'admin_c', 'auth']
		widgets = {'auth': MultiTextInput()}

		help_texts = {
			'auth': 'Enter names of users which can edit this object (space separated; '
			'and yes, validation is somewhat broken (values disappear on error - just reload))'
		}

	def __init__(self, *args, **kwargs):
		super(MntForm, self).__init__(*args, **kwargs)
		print(args, kwargs)
		
		#if self._create:
		#	self.fields['auth'].text("noot")


class MntInitialForm(MntForm):
	class Meta:
		model = Maintainer
		fields = ['handle', 'description']


class ContactForm(WhoisObjectFormMixin, forms.ModelForm):
	class Meta:
		model = Contact
		fields = ['handle', 'name', 'mnt_by']

	def __init__(self, *args, **kwargs):
		super(ContactForm, self).__init__(*args, **kwargs)

		if "mnt_by" in self.fields:
			self.fields['mnt_by'].queryset = Maintainer.objects.filter(auth=self._user).distinct()


class ContactInitialForm(ContactForm):
	class Meta:
		model = Contact
		fields = ['handle', 'name']


class InetNumForm(MntFormMixin, WhoisObjectFormMixin, forms.ModelForm):
	prefix = forms.CharField()
	protectedFields = ['protocol', 'parent_range', 'mnt_by', 'prefix']

	class Meta:
		model = InetNum
		fields = ['handle', 'protocol', 'parent_range', 'prefix', 'name', 'description', 'origin_as', 'mnt_by', 'mnt_lower', 'admin_c']

	def __init__(self, *args, **kwargs):
		super(InetNumForm, self).__init__(*args, **kwargs)

		if self._editLower:
			for key in self.protectedFields:
				self.fields[key].disabled = True

		mnts = self._user.maintainer_set.all()
		#self.fields['parent_range'].queryset = InetNum.objects.filter(Q(mnt_by__in=mnts) | Q(mnt_lower__in=mnts))
		#if not self._create:
		#	self.fields['parent_range'].queryset |= InetNum.objects.filter(pk=self.instance.pk)

		#self.fields['parent_range'].queryset = self.fields['parent_range'].queryset.distinct()
		self.fields['parent_range'].queryset = InetNum.getMntQueryset(mnts, self.instance, "parent_range")
		self.fields['origin_as'].queryset = ASNumber.getMntQueryset(mnts, self.instance, "origin_as")

	def clean_prefix(self):
		# make sure this is a subnet we're getting
		net = self.cleaned_data['prefix'].lower()
		IP46CIDRValidator(net)

		try:
			net = ipaddress.ip_network(net)
		except ValueError as e:
			raise forms.ValidationError(str(e))

		return net

	def clean_parent_range(self):
		parent_range = self.cleaned_data.get('parent_range', None)

		if parent_range.origin_as.count() > 0:
			raise forms.ValidationError("Parent range has origin as set")

		# allow parent range to be unset for already present objects
		if not parent_range and (self._create or not self._create and self.instance.parent_range):
			raise forms.ValidationError("Parent range must be set")

		if not self._create and parent_range:
			# make sure we don't have circular dependencies
			obj = parent_range
			while obj.parent_range:
				if obj.pk == self.instance.pk:
					raise forms.ValidationError("No circular dependencies allowed")
				obj = obj.parent_range

		return parent_range

	def clean(self):
		cleaned_data = super(InetNumForm, self).clean()

		if not self._editLower:
			if not self.errors:
				if not self._create and self.cleaned_data['origin_as']:
					if self.instance.inetnum_set.count() > 0:
						ranges = ", ".join(map(str, self.instance.inetnum_set.all()))
						raise forms.ValidationError("You cannot set an origin as if there are already existing subranges (%s)" % (ranges))

				prefix = cleaned_data['prefix']
				parent = cleaned_data['parent_range']
				if parent:
					parentNet = parent.getNetwork()

					if cleaned_data['protocol'] != parent.protocol:
						raise forms.ValidationError("Protocol type for prefix must be same as parent network")

					# check if in parent block
					if prefix.network_address not in parentNet or prefix.prefixlen < parentNet.prefixlen:
						raise forms.ValidationError("Prefix must be inside parent network range")


					# check if parent block has net that overlaps with us
					for otherNet in parent.inetnum_set.all():
						if self.instance and self.instance.pk == otherNet.pk:
							continue

						if otherNet.getNetwork().overlaps(prefix):
							raise forms.ValidationError("The given prefix overlaps with network %s" % otherNet.handle)

				# check if subnets to this subnet are (still) in current network
				if not self._create:
					for subnet in self.instance.inetnum_set.all():
						if subnet.getNetwork().network_address not in self.instance.getNetwork():
							raise forms.ValidationError("Subnet %s with %s is not in block anymore" % (subnet, subnet.getNetwork()))

				self.instance.address = str(prefix.network_address)
				self.instance.netmask = prefix.prefixlen

		return cleaned_data


class ASBlockForm(MntFormMixin, WhoisObjectFormMixin, forms.ModelForm):
	protectedFields = ['parent_block', 'asBegin', 'asEnd', 'mnt_by']

	# FIXME: Filter blocks
	class Meta:
		model = ASBlock
		fields = ['handle', 'parent_block', 'asBegin', 'asEnd', 'name', 'description', 'mnt_by', 'mnt_lower', 'admin_c']

	def __init__(self, *args, **kwargs):
		super(ASBlockForm, self).__init__(*args, **kwargs)

		if not self.instance or self.instance and self.instance and self.instance.parent_block:
			self.fields["parent_block"].required = True
		if self.instance and self.instance.pk:
			self.fields["parent_block"].disabled = True

		mnts = self._user.maintainer_set.all()
		self.fields['parent_block'].queryset = ASBlock.getMntQueryset(mnts, self.instance, "parent_block")

	def clean_parent_block(self):
		parent_block = self.cleaned_data.get('parent_block', None)

		# allow parent range to be unset for already present objects
		if not parent_block and (self._create or not self._create and self.instance.parent_block):
			raise forms.ValidationError("Parent block must be set")

		if not self._create and parent_block:
			# make sure we don't have circular dependencies
			obj = parent_block
			while obj.parent_block:
				if obj.pk == self.instance.pk:
					raise forms.ValidationError("No circular dependencies allowed")
				obj = obj.parent_block

		return parent_block

	def clean(self):
		cleaned_data = super(ASBlockForm, self).clean()

		if not self.errors:
			asBegin = cleaned_data['asBegin']
			asEnd = cleaned_data['asEnd']
			parent = cleaned_data['parent_block']
			# check if somebody is already using this block

			# check if in range
			if asBegin > asEnd:
				raise forms.ValidationError("AS beginning must be smaller or equal to AS end")

			if parent:
				if parent.asnumber_set.count() > 0:
					raise forms.ValidationError("The parent AS block is already references by following AS number objects: %s" % (", ".join(map(lambda _x: _x.handle, parent.asnumber_set.all())),))

				# check if same range
				if not (asBegin >= parent.asBegin and asEnd <= parent.asEnd):
					raise forms.ValidationError("AS beginning and end must be inside the range of the parent AS block")

				if parent.asBegin == asBegin and parent.asEnd == asEnd:
					raise forms.ValidationError("The range of this block cannot be the same range AS the parent AS block")

				# check for overlap with other asblocks
				for block in parent.asblock_set.all():
					if self.instance and self.instance.pk and block.pk == self.instance.pk:
						continue

					if block.asBegin <= asBegin <= block.asEnd or block.asBegin <= asEnd <= block.asEnd or \
						asBegin <= block.asBegin <= asEnd or asBegin <= block.asEnd <= asEnd:
						raise forms.ValidationError("Block overlaps with block %s" % block.handle)

			if not self._create:
				# check if subblocks are still in range
				for subblock in self.instance.asblock_set.all():
					if not (asBegin <= subblock.asBegin <= asEnd and asBegin <= subblock.asEnd <= asEnd):
						raise forms.ValidationError("Subblock %s (%s - %s) is not contained in this block anymore" % (subblock, subblock.asBegin, subblock.asEnd))

				# check if asnumbers are still in range
				for asnumber in self.instance.asnumber_set.all():
					if not (asBegin <= asnumber.number <= asEnd):
						raise forms.ValidationError("AS %s (%s) is not contained in this block anymore" % (asnumber, asnumber.number))


		return cleaned_data


class ASNumberForm(MntFormMixin, WhoisObjectFormMixin, forms.ModelForm):
	protectedFields = ['asblock', 'number', 'mnt_by']

	class Meta:
		model = ASNumber
		fields = ['handle', 'asblock', 'number', 'volatile', 'name', 'description', 'mnt_by', 'mnt_lower', 'admin_c']

	def __init__(self, *args, **kwargs):
		super(ASNumberForm, self).__init__(*args, **kwargs)

		if not (self.instance and self.instance.pk):
			self.fields["asblock"].required = True
		else:
			self.fields["asblock"].disabled = True

		mnts = self._user.maintainer_set.all()
		self.fields['asblock'].queryset = ASBlock.getMntQueryset(mnts, self.instance, "asblock")

	def clean(self):
		cleaned_data = super(ASNumberForm, self).clean()

		if not self.errors:
			number = cleaned_data['number']
			block = cleaned_data['asblock']

			# belongs to asblock?
			if number < block.asBegin or number > block.asEnd:
				raise forms.ValidationError("AS number is not inside AS block")

			# does an entry already exist?
			try:
				otherAS = ASNumber.objects.get(number=number)
				if not (self.instance and self.instance.pk and self.instance.pk == otherAS.pk):
					raise forms.ValidationError("This AS number is already represented by %s" % otherAS.handle)
			except ASNumber.DoesNotExist:
				pass

			# has already other asblock?
			if block.asblock_set.count() > 0:
				raise forms.ValidationError("The given AS block is already references by following sub AS blocks: %s" % (", ".join(map(lambda _x: _x.handle, block.asblock_set.all())),))